A conventional arrangement of dual wheels mounted to a hub is shown in FIG. 1. This arrangement is common in the commercial heavy truck industry. For dual wheel mounting, the hub has protruding studs. The inner dual wheel with tire is assembled onto the hub, then the outer dual wheel with tire is assembled to the hub, and then a flange nut secures both wheels to the hub assembly. Wheels can be centered on the hub or by use of conical or ball seat nuts so that the wheels are centered using the studs. The conventional arrangement shown in FIG. 1 tends to have relatively high stresses in the disc area, the entire wheel often must be replaced in the event of the wheel cracking under load (which can result in higher replacement costs), the studs tend to protrude a further distance from the hub so that they can go through both wheel discs and be secured with a nut, and fretting and corrosion can occur between the two discs of the dual wheels.
Another conventional arrangement of dual wheels is shown in FIGS. 2A-2C. This design, also typically used on heavy trucks, utilizes two-piece bolt-together wheels. Like one-piece wheels, two-piece bolt-together wheels are assembled to the vehicle using studs and flange nuts or conical or ball seat nuts. Dual wheels may also be made as a multi-piece design utilizing flat base rims, side rings and/or locking rings. The cast hub of FIGS. 2A-2C tends to be relatively heavy and the assembly tends to be relatively difficult to align properly resulting in poor ride quality, the risk of wheels becoming loose, imbalance, chording of rims if clamps are over-tightened and difficulty in reaching the inflation valve of the inner dual.
Another conventional arrangement of dual wheels on commercial vehicles is shown in FIG. 3. This arrangement uses a cast hub with two demountable rims. The demountable rims are typically separated with a spacer band and secured by a clamp which is attached with hub studs and nuts. Some construction type vehicles utilize this design because of the robustness of the cast hub and the space needed for the hub drive train.
Another conventional arrangement is shown in FIG. 4. This arrangement uses cap screws or bolts to secure each dual wheel directly to the hub. The arrangement of FIG. 4 tends to use a relatively significant number of fasteners to secure each rim assembly. Also, maintenance tends to be difficult due to the high number of fasteners, and extremely limited access to the cap screws for the inner dual.
Yet another arrangement is described in U.S. patent application Ser. No. 12/365,252 publication number US 2010/0194180 A1 published on Aug. 5, 2010, the disclosure of which is incorporated by reference herein. This arrangement uses a spindle with a separate hub mount bearing. Two wheels are then attached to the hub mount bearing. This arrangement tends to include excessive weight, potential for misalignment (which in turn can cause poor ride quality), imbalance, and restricted access to the inflation valve of the inner dual.